Tow to charge?

[Newton]

that sounds like a real easy, dreamy idea, but it doesn't hold merit:

A) any 'portable' generator, if there even is such a thing, with 240v output, CONTINUOUSLY, for HOURS on END, at any amount of output, such as 30amps, would not only take a HUGE amount of fuel, but would not be 'portable' for any such a reasonable situation... it's just not reality. The weight of the generator, and the additional 'fuel' you now would need to CARRY in the truck, negates all the 'power' you might be able to generate. You've now wasted MILES to get where you are going, so you actually come up SHORTER than if you had NOT carried it to begin with.

I have a 12kW in my boat (Lugger brand). It uses around 1.5 gph or less and when it had to be repaired the (very large) diesel mechanic carried it up the stairs. (It might have been two guys, I wasn’t there but it was no big deal to them.). It is 50a/240V and is used to charge my house battery bank at 100A (24V) as well as the watermaker and other things. Non marine versions might be a bit heavier because of the radiator.

Sponsored

 

[Newton]

Why not get the Powerboost with the 7.2kW generator onboard? One hour of that would give you a lot more range than trying to tow for an hour. Unfortunately the 250 has a smaller onboard generator which is weird.

 

[Maquis]

Why not get the Powerboost with the 7.2kW generator onboard? One hour of that would give you a lot more range than trying to tow for an hour. Unfortunately the 250 has a smaller onboard generator which is weird.

I don’t think that’s correct. 7.2 KW of regen would barely be noticeable. I can’t find the source, but I seem to remember reading that the max regen was something like 75 KW.

 

[potato]

Why not get the Powerboost with the 7.2kW generator onboard? One hour of that would give you a lot more range than trying to tow for an hour. Unfortunately the 250 has a smaller onboard generator which is weird.

Regen can charge way, way faster than 7 kW. Like 10 or 20 times faster. Flat towing is absolutely doable, maybe illegal but in a pinch I wouldn't hesitate to do it.

 

[Newton]

I think that one of us is confused. Regen is braking energy, right? If I’m going down a slope where my terminal velocity is 40mph (its a very carefully calibrated slope) and my cruise control is set to 40mph, there will be zero regen.

If I’m being towed behind a car doing 40mph and somehow I enable the cruise control to 40 mph, there will be zero regen energy until the tow vehicle speeds up above 40, at which point there will be lots of smoke from the tow vehicle’s tires. The only way to get energy is to have a braking force against the tow vehicle which will be transmitted through the tower’s tires, the tow rope and to the tires of the Ford, which will be as likely to slide as they will be to transmit energy to the motors. This seems inefficient and unsafe and I don’t think that you will get near the amount of energy that you think from it.

I live in an area with lots of mountains and have not noticed that regen is all that magial. On a long nearly continuous downhill run over about 40 minutes I think my Kia gained 1% on the battery. Volkswagen is somewhat anti-regen because their tests show that coasting is generally better. That is kind of a side issue, but goes to the point that there isn’t a huge amount of energy that you can tap by towing the truck.

I had the thought that if you have a Cummins diesel, there are high output alternators available (used for ambulances and boats) that could be used to implement your own version of “pro power” at a fairly reasonable cost with a suitable inverter. Look up the trade name “Balmar.” (Obviously you can do this with any engine, but brackets exist already for the Cummins.)

 

[RedLightning86]

I can think of lots of reasons why it shouldn't work... but am looking forward to seeing someone do it on YouTube, LOL. I know one of the charging gurus did it with a Tesla once, just enough to get it to a charger. Of course, could have just towed it to the charger...

(My understanding of towing the Lightning is that it can be done via the Neutral and and that button in back of the gear shift. Just not charged then.)

 

[hturnerfamily]

agreed: REGENERATION can be misleading to many, as it may make us assume that you are somehow 'gaining' miles, although that is actually an impossibility, as physical laws prescribe. What you are 'gaining' is actually the 'loss of battery power' that would have normally occurred during those miles, because, after all, you didn't really 'use' any battery power to travel them.

in other words, like coasting, where you are allowing the laws of gravity, inertia, momentum, etc., to help you forward, you are simply moving without any of your own 'power'.

What's interesting about REGENERATION in vehicles is the more 'sudden' regaining of that power, but in a much SHORTER timeframe than if using Coasting.
For instance, if you REGEN down a hill and 'recapture' power, you may have traveled TWICE as FAR if you had Coasted, meaning that while you REGEN'd power, you now have to USE power to go that 'second' half of the same comparison, in length of travel.
This is why some of us don't necessarily assume that REGEN is 'giving' you anything that you wouldn't have, otherwise. Yes, it's great to have, to 'feel' the Regen happening, especially when you DON'T have to apply the physical brakes, but that very same 'slowing' of the vehicle, which otherwise would have traveled farther while Coasting, is, at the same time, costing you in the long-run, in most situations.

Now, if you use ONE specific test, you might come up with the OPPOSITE side of the equation: traveling ONLY downhill for the majority of a trip. So, if you have a trip that starts at 3,000' in elevation, and you are traveling to a destination that is at 200' elevation, you will most certainly make good use of REGENERATION during most of the whole trip. Yes, you will use LESS energy, overall, than if you were on FLAT LAND, or certainly compared to the opposite travel, going UPHILL most of the way. This is a perfect example of EVs getting 'great' mileage, although most any vehicle would, also.
But, in the end, if your travels takes you BACK to your starting point, you will now be going back UPHILL ... negating those same efficiencies you saw on the original trip, giving more of an 'average' for the whole set of miles. You'll probably then find that, in the same conditions, you will have the same average as you normally would, including FLAT LAND travels of the same total miles.
If you Coasted, rather than using REGENERATION, in that same scenario, the outcome would be the same. There is no physical law that allows for us to 'make miles', or 'make power', in the course of travels, over the long term.

You can test this in 'SPORT' Mode, versus 'NORMAL' Mode, over the same exact number of miles and the same exact route. Let the truck do it's regeneration as much as possible, maintaining the same 'average' speed for the whole trip. While even this test is almost impossible to duplicate between the two modes, it will give you some feedback on how close the two are, outcome wise, to the same miles/per kWh used during those miles.

and, having said 'all that', I use 'SPORT' Mode exclusively, in all situations, and in all travels, and EVEN while towing our camper.

I find that, for me, this mode, creating a great amount of REGENERATION, allows me to comfortably drive with very little instances of using the Physical Brakes, AND it gives me support when coming off the 'GO' pedal... already slowing me down, especially in high traffic situations.
There are areas of terrain and certain times that I might change to 'NORMAL' Mode, like coming down a long, long set of mountainous interstate, but those times are very rare, and much of the time I wonder why I even did it.

and, one question that I have is: would we change REGENERATION mode more often IF we had a more easy way to do that?
My wife's EV9 has steering wheel 'paddles' that allows for that, even into one-pedal mode. So, the left paddle ADDS regeneration from 'none'(coast), to 'one-pedal mode', in four incremental steps, each more regenerative than the last.
The right paddle simply REMOVES regeneration, or removing one-pedal mode, all ON THE FLY while you are driving, with NO requirement to interact with any screen. It's wonderful, and yes, I do tend to use these A LOT since it's right there in your hands. You won't even realize how much this is useful until you have this option available...

my tow youngest Sons both have Chevy BOLTS, and both have steering wheel REGENERATION paddles, too, but they work differently ... meaning that Chevy allows you to 'HOLD' the paddle to continue to use the REGEN, and then RELEASE the paddle to go back to 'Normal' driving, or even COASTING, etc. These are 'on demand' type paddles, rather than each one 'setting' a Regen level. The left ADDS regeneration as long as you hold it, and then even into One-Pedal if you continue, and the right REMOVES Regen as long as you hold it(coating), etc.

I understand, though, that FORD, since using an existing platform, the F150 line, probably did not want to go too far abound from it's 'normal' steering wheel setup to add these REGEN paddles, or something similar. I don't blame them, but it IS a very nice option to have, when you know how it works on other vehicles. What this does, though, is then require Ford to establish 'set' Modes, which incorporate certain amounts of REGEN, built in. If users/drivers want less, or more, they have to change to a different mode, or to ADD One-Pedal option, at least on some modes.

 

[jjerabek]

agreed: REGENERATION can be misleading to many, as it may make us assume that you are somehow 'gaining' miles, although that is actually an impossibility, as physical laws prescribe.

Physical laws prescribe you cannot get something out of nothing, true. However, again, this is the hypothetical use case:

You are going to a remote place. You need 2 work trucks. You need power source and it happens to be that your 2nd vehicle is a giant portable 100kW battery with a 7.2kW pro power onboard. What is the potential in you having the second truck a HD diesel truck that is optimized to tow be the source of energy for you 4 wheel drive battery with inverter motors in it?

Back to physics: If you are going downhill in your F150L at 70mph and you need equivalent of 65mph to overcome aerodynamic drag, tire friction, and just to propel the weight, you are only regenerating at 5mph speed to use a crude example.

However, what if you were at 60mph using 0 energy for the factors above (because that energy is provided by the HD diesel truck towing), how much and how quickly can you put the energy from the torque of the diesel engine into the battery?

The one example we have from real world is in the video posted in the thread where a Tesla being towed at 30 km/h can return about 1kW of energy into the battery EVERY 1 km being towed. In theory, grossly underestimating other energy losses through drivetrains and drag, you should be able to return about 3kW of energy into your battery being towed at 90km/h every km, and consequently, within 25km(like 15 miles I think) you should generate 75kW of energy. Furthermore, at 90km/h you should cover those 25km in 17 minutes (in THEORY. You would have to figure out a way to be able to modulate your regen to keep it at the max regen without applying friction brakes on the Lightning).

Again, disclaimer, the idea is based on the hypothesis that you need 2 cars wherever you are going, there is no charging infrastructure, and you wand you 4-wheel-drive battery along.

 

[Yellow Buddy]

I think that one of us is confused. Regen is braking energy, right? If I’m going down a slope where my terminal velocity is 40mph (its a very carefully calibrated slope) and my cruise control is set to 40mph, there will be zero regen.

If I’m being towed behind a car doing 40mph and somehow I enable the cruise control to 40 mph, there will be zero regen energy until the tow vehicle speeds up above 40, at which point there will be lots of smoke from the tow vehicle’s tires. The only way to get energy is to have a braking force against the tow vehicle which will be transmitted through the tower’s tires, the tow rope and to the tires of the Ford, which will be as likely to slide as they will be to transmit energy to the motors. This seems inefficient and unsafe and I don’t think that you will get near the amount of energy that you think from it.

I live in an area with lots of mountains and have not noticed that regen is all that magial. On a long nearly continuous downhill run over about 40 minutes I think my Kia gained 1% on the battery. Volkswagen is somewhat anti-regen because their tests show that coasting is generally better. That is kind of a side issue, but goes to the point that there isn’t a huge amount of energy that you can tap by towing the truck.

I had the thought that if you have a Cummins diesel, there are high output alternators available (used for ambulances and boats) that could be used to implement your own version of “pro power” at a fairly reasonable cost with a suitable inverter. Look up the trade name “Balmar.” (Obviously you can do this with any engine, but brackets exist already for the Cummins.)

Regen is not braking energy.

The motors that we have in the truck are tied to inverters. Convert DC energy into mechanic spinning energy to propel the vehicle forward.

When we let off the accelerator, we have momentum. That momentum will continue spinning the motor if we do not disconnect it. If we leave it connected, the momentum will end up “creating” energy or “regenerating” energy that’s already been spent to get up to speed and feeding it back into the battery pack.

The pikes peak Lightning for example can output 1500kW of power and has the ability to regen 600kW. That’s more power than our motors output! That power generation, is the conversion of kinetic energy back into DC power, which slows us and makes us think it’s braking.

Theoretically I could be dropped on top of a hill via helicopter and I will “regen” all the way down, having spent nothing from my own battery pack my truck will actually be creating energy - of course the corresponding energy would’ve been spent by the helicopter.

So going back to towing…

If you tow and hit the brakes, you will be fighting against the friction brakes, you will not capture a ton of energy and you will cause all sorts of issues for yourself and the tow vehicle.

If you throw it into neutral, you will free roll with the motors semi-disconnected, you will not be generating any energy but you can create waste heat which is why we shouldn’t flat tow.

If you are looking to refill your battery pack, you keep it in drive. You roll on the accelerator to disconnect auto hold. The tow vehicle is the one spending energy to pull you forward, simulating the pull of gravity downhill which spins your motors and then refills your battery. You will be taxing the tow vehicle more than a normal trailer as you will not be free rolling, the faster you pull the faster the regen will be until its its max rate.

 

[Yellow Buddy]

Again, disclaimer, the idea is based on the hypothesis that you need 2 cars wherever you are going, there is no charging infrastructure, and you wand you 4-wheel-drive battery along.

And insistent that you actually drive both.

The better answer is to throw the Lightning onto a trailer. Tow it with the HD diesel. You’ll end up spending about the same amount of energy without the safety concerns.

I know I keep saying it - possible but not recommended. There’s better ways to skin this cat.

 

[hturnerfamily]

probably all of us, at one time or another, have had those 'people'(you know, the ones that DON'T own an EV, and sometimes don't even 'believe' in EVs) claim that 'all we have to do' is add an Alternator to our spinning wheels, and 'voila!', we'd have it licked! Yes, well, a novel idea, for sure, and that works to keep a tiny 12v battery supply with most of it's trickle charge while the engine is running in most 'other' vehicles, but we are talking about a HUGE very powerful Battery Pack, at 400+/- volts, with inverters, converters, and electric MOTORS that require a HUGE amount of power. This is not where an 'alternator' makes any sense.

The second reaction is typically: "why don't you just throw a generator in the back of your truck, 'just in case'?"... sure, that, again, is a novel thought, but is not realistic to any 'answer' to range. The shear WEIGHT of any additional 'generator', AND all the additional FUEL you'd need to carry, NEGATES the whole REASON for having it: it would simply create a LOWER range or miles, to begin with.

It's easy to just assume that no one has ever thought of these 'answers' before, but engineers are not dumb. They are trained to ask themselves these very same questions, and to look for LOGICAL and REASONABLE answers.
What happens, though, is that Real Life gets in the way of 'simple answers', as we don't live our lives, or drive, in a bubble, or in a Perfect World.
If an Alternator was the 'simple' answer, sure, we'd all already have one.
If a Generator was the 'simple' answer, sure, we'd all be offered one as an 'optional' add-on to our trucks.
If a Larger BATTERY was the 'simple' answer, we'd all BALK at the huge additional cost.

No, there are little 'simple' answers to anything Battery Powered, or Engine Powered, or Coal Powered. It's all about physics, the laws of gravity, science, and logic.

REASONABLE answers are similar to what we already have:
A) a fine vehicle that has 'reasonable' range
B) a fine vehicle that has 'reasonable' cost
C) a fine vehicle that works just as it should

There will always be those who propose additional 'needs', but generally speaking, you own a machine that does exactly what it should, and does it VERY WELL. We are all blessed.

 

[wighty]

plus, you would find that the 'towing' of an EV, while the EV is IN GEAR, would be extremely taxing on ANY tow vehicle, and would waste more fuel in the tow vehicle that negates the whole reason...

I'm in agreement this is overall a bad idea (I like the generator + evse idea better)... But there are some theoretical benefits for it:

 

[invertedspear]

If you tow and hit the brakes, you will be fighting against the friction brakes, you will not capture a ton of energy and you will cause all sorts of issues for yourself and the tow vehicle.

I agree with most everything you said except this particular statement. Applying the brake pedal does not immediately apply friction brakes. Friction brakes are only used when you are asking for more "slow down" than the engine regens can provide, or when you are at very slow speeds. You can see this using the power distribution screen on the dash which will show you how much each engine is regenerating, and when it maxes out what it can do the friction brakes begin.

 

[Yellow Buddy]

I agree with most everything you said except this particular statement. Applying the brake pedal does not immediately apply friction brakes. Friction brakes are only used when you are asking for more "slow down" than the engine regens can provide, or when you are at very slow speeds. You can see this using the power distribution screen on the dash which will show you how much each engine is regenerating, and when it maxes out what it can do the friction brakes begin.

Correct, I was oversimplifying it.

The problem is in a towing situation it’s very difficult to tell when the brakes are being blended (regen vs friction)

 

[pdegenkolb]

so, let's look at the real-world LOGISTICS of trying to make this 'work':

- first, the LIGHTNING would have to be 'ON'
- next, someone would have to put the truck in GEAR, before even starting to tow it
and would likely have to continue RIDING in the truck
- next, the truck would have NO stopping power, use of brakes, etc, in 'Normal' or 'Sport' mode
- the truck would also ALWAYS be applying the brakes CONSTANTLY if in One-Pedal mode

so, you'll find that trying to 'tow' an EV while it is 'regenerating' power is not a 'real' thing...

I am trying to look at this logically. :
What is the difference between pulling the F-150 and having the F-150 (or any electric car) on a downhill grade with a greater grade than rolling friction?
Forgetting the inherent inefficiency, the question here is if it would work. Will it?
Yes, someone would have to be in the F-150 as well as having someone in the tow vehicle. But, if you have two trucks along in the first place, that should not be a logistical problem. (Legal, maybe, but not logistical.)
I do not know about Canada, but in California, having a person in a "normally towed vehicle" is illegal. However, if you are towing one vehicle with a tow rope vice a tow bar, the towed vehicle has to have a driver capable of controlling the vehicle. (The law hat o allow for certain emergencies.)
Next, one pedal or two pedal, if there is capacity to slow the vehicle via electrical braking, the friction brakes should never go on. As such, the driver of the Lightning would have the responsibility of maintaining a "power setting" (accelerator pedal position) consistent with some maximum charging rate. (I think if I were testing this on a Lightning, I would hold at 50KW or less. At least initially.)

On another post, I am not convinced that the electro-mechanical losses would be that much different with this method than a generator. I suspect it would be less efficient overall, but both faster and easier than toting a 10KW generator.
Personally, I think this would work. Would it be worth it? I do not know. Legally it would be questionable, but so are many worthwhile ventures. It might mess with your warranty - if Ford could prove it.
I would love to see a test as I have had the same question, although without the same resources.

Sponsored